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Overview
| Comment: | Performance improvements in btreeParseCell() by inlining the varint decoder. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | btree-opt |
| Files: | files | file ages | folders |
| SHA1: |
faab0ed928074f3ec7c25e1a2058414f |
| User & Date: | drh 2015-06-19 18:24:37.928 |
Context
|
2015-06-19
| ||
| 20:08 | Fix corner cases involving corrupt varint values in record headers. (Closed-Leaf check-in: 3189116b42 user: drh tags: btree-opt) | |
| 18:24 | Performance improvements in btreeParseCell() by inlining the varint decoder. (check-in: faab0ed928 user: drh tags: btree-opt) | |
| 17:19 | Add the MemPage.xParseCell method and provide various implementations (variations on the former btreeParseCellPtr()) depending on the page type. (check-in: 41d03d883c user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
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static void btreeParseCellPtr(
MemPage *pPage, /* Page containing the cell */
u8 *pCell, /* Pointer to the cell text. */
CellInfo *pInfo /* Fill in this structure */
){
u8 *pIter; /* For scanning through pCell */
u32 nPayload; /* Number of bytes of cell payload */
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
assert( pPage->leaf==0 || pPage->leaf==1 );
assert( pPage->intKeyLeaf || pPage->noPayload );
assert( pPage->noPayload==0 );
assert( pPage->intKeyLeaf );
assert( pPage->childPtrSize==0 );
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static void btreeParseCellPtr(
MemPage *pPage, /* Page containing the cell */
u8 *pCell, /* Pointer to the cell text. */
CellInfo *pInfo /* Fill in this structure */
){
u8 *pIter; /* For scanning through pCell */
u32 nPayload; /* Number of bytes of cell payload */
u64 iKey; /* Extracted Key value */
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
assert( pPage->leaf==0 || pPage->leaf==1 );
assert( pPage->intKeyLeaf || pPage->noPayload );
assert( pPage->noPayload==0 );
assert( pPage->intKeyLeaf );
assert( pPage->childPtrSize==0 );
pIter = pCell;
/* The next block of code is equivalent to:
**
** pIter += getVarint32(pIter, nPayload);
**
** The code is inlined to avoid a function call.
*/
nPayload = *pIter;
if( nPayload>=0x80 ){
u8 *pEnd = &pIter[9];
nPayload &= 0x7f;
do{
nPayload = (nPayload<<7) | (*++pIter & 0x7f);
}while( (*pIter)>=0x80 && pIter<pEnd );
}
pIter++;
/* The next block of code is equivalent to:
**
** pIter += getVarint(pIter, (u64*)&pInfo->nKey);
**
** The code is inlined to avoid a function call.
*/
iKey = *pIter;
if( iKey>=0x80 ){
u8 *pEnd = &pIter[7];
iKey &= 0x7f;
while(1){
iKey = (iKey<<7) | (*++pIter & 0x7f);
if( (*pIter)<0x80 ) break;
if( pIter>=pEnd ){
iKey = (iKey<<8) | *++pIter;
break;
}
}
}
pIter++;
pInfo->nKey = *(i64*)&iKey;
pInfo->nPayload = nPayload;
pInfo->pPayload = pIter;
testcase( nPayload==pPage->maxLocal );
testcase( nPayload==pPage->maxLocal+1 );
if( nPayload<=pPage->maxLocal ){
/* This is the (easy) common case where the entire payload fits
** on the local page. No overflow is required.
|
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